You mention that this might be used as a fund-raising quilt and that you've though of sending it out to be quilted? In my experience, anyone who is a NON-quilter (WHAT??? - there are people out there that don't quilt?
so sad for them!
) doesn't really know custom from overall quilting. They will buy tickets based on 1) do they want to support the cause and 2) does the item appeal to them. Your quilt already has "Wow" factor based on the beautiful design and color choices. Of course you don't want to quilt it in a way which detracts from that, but a pretty allover design would look fine and allow the quilt to be finished at a reasonable cost. Baptist fans would be in keeping with the civil war timeframe, or perhaps a pretty feather design.
If you prefer to do it yourself, I've sketched one idea on your photo. Straight lines through the chains, a simple feather in the triangular areas, and SID the elements of each block. (If I were longarming it I would use CC (continuous curve) in the block elements, but I don't know how difficult that might be to do on a domestic machine.) Maybe a feather here and there in some of the larger areas. And a complementary feather border.
Can't wait to see this finished, I really love this quilt!
Andi